When coupling mobile devices with devices of the vehicle, it is necessary to use compatible data protocols that make it possible for the in-vehicle device to process the data received from the mobile device and conversely for the mobile device to process the data of the in-vehicle device. When coupling a mobile navigation device with the vehicle, it is known for example to couple the mobile navigation system with in-vehicle devices via the interface for an automotive diagnostic system (the so-called OBD-II jack). Vehicle-specific information is supplied to the mobile navigation device via this interface, in particular information relevant to the environment. This information may be used for a fuel-optimized navigation function of the mobile navigation device.
German Application No. DE 199 21 533 describes a communication system of a motor vehicle. This communication system includes a mobile telephone and an audio and/or information system, which is installed in the motor vehicle and which includes a receiving device and an acoustic output unit as well as a microphone for implementing a hands-free speaking function. The communication system allows for a voice and/or data transmission between the mobile telephone and the audio and/or information system via a wireless link. Telephone calls received by the mobile telephone are able to be output via the acoustic output unit. The communication between the mobile telephone and the audio and/or information system installed in the motor vehicle occurs via a second radio link, which is developed as a bidirectional short-distance link. The communication between the system installed in the motor vehicle and the mobile telephone makes it possible to operate the mobile telephone via operating elements of a radio of the vehicle for example. The mobile telephone may furthermore be used as a remote control for the radio. Finally, other vehicle functions, which are connected via a suitable bus, may also be controlled by the mobile telephone.